The presnt invention relates in general to noise abatement techinques and in particular to a new and useful method and apparatus for reducing noise generated by transverse vibrations in an elongated member, which vibrations are transverse to a major axis or dimension of the elongated member.
Various approaches to noise abatement are known particularly for elongated percussion tools. U.S. Pat. No. 4,030,553 to Rockwell for example discloses noise dampening within percussion tools by providing structural discontinuities selectively placed within the tools relative to nodes or anti-nodes of vibration for the tools. These structural discontinuities typically take the form of threaded joints.
U.S. Pat. No. 2,680,333 to Calosi relates to a vibration control device including threaded engagements between an outer sleeve and inner tool.
Approaches are also known for dampening the vibration of flat panels or sheets. U.S. Pat. No. 4,023,651 to Healiss discloses the use of flexible pads secured to metal sheets by magnetic attraction for this purpose.
Other U.S. Patents which are relevant to the present invention are U.S. Pat. No. 1,609,136 to Stevens which discloses the use of an elastic collar; U.S. Pat. No. 3,168,324 to Kennell which discloses a structure for limiting the vibration of a tool bit; U.S. Pat. Nos. 3,179,185 to O'Farell which shows a damper for dampening lateral vibrations; 2,685,274 to Liddicoat which utilizes an elastic collar; 4,195,713 to Hatjer et al which shows a sandwich structure for dampening vibration; 3,662,855 to Adams et al; and 3,848,931 to Swisher.